Automatic, high-speed counting and filling devices are routinely used in a number of industries to count and package predetermined quantities of discrete objects. For example, pharmaceutical manufactures use such devices to package pills, tablets, capsules and similar discrete dosage forms. Automatic counting and filling machines are also used in the hardware industry to count and package nuts, bolts, screws and similar hardware, and by food manufactures to count and package discrete edible items, such as nuts and candies.
To meet the requirements of, for example, the pharmaceutical industry, such devices must be capable of rapidly filling a large number of containers, typically on the order of one hundred to several hundred containers per minute, with a quantity of product which corresponds to the predetermined quantity. In addition, the apparatus should be able to accurately distinguish chipped, broken or otherwise damage product from intact product and segregate containers containing damage product for additional processing. Finally, since automatic counting and filling devices are typically used to package several different products, the device should be designed such that it can be easily disassembled and thoroughly cleaned in order to minimize down time.
Several different types of automatic counting and packaging devices are currently available. In one such device, product is continuously dropped from a hopper onto a vibrating feed tray which advances the product downstream to a photosensor for counting. When a quantity of product equaling the predetermined quantity has been counted by the photosensor, the product is directed into a container. Such devices present a number of disadvantages. First, a considerable distance must be provided between the hopper and the photosensor to ensure that the feed tray has sufficiently singularized the product to be accurately counted by the photosensor. In some cases up to three vibrating feed trays must be employed for this purpose. Second, the design of known feed trays is such that the tray must be vibrated at a relatively low frequency and amplitude to ensure that the product does not move downstream with excessive hop, i.e., the product is not elevated too high off the surface of the tray. Accordingly, the product cannot be advanced along the feed tray at optimum speeds, which results in generally unacceptable filling rates.
It is, therefore, an object of the invention to provide a feed tray that will completely singularized a quantity of objects over a linear distance which is significantly reduced from that required by prior art feed trays.
It is a further object of the invention to provide a feed tray which permits a feed rate significantly higher than the rates permitted by prior art feed trays.